Defoaming agent for pulp and paper stock



te 5t Fatented Aug. 16, 1955 ice Clark E. Snoolr, East Orange,

Chemical Company, New Jersey N. 3., assignor to Nopco Harrison, N. l, acorporation of N 0 Drawing. Application March 31, 1949,

Serial No. 84,769

12 Claims. or. 252-353 This invention relates to a new and improveddefoaming agent and more particularly to a new and improved defoamingagent which is particularly suitable for use in the paper industry.

A number of defoaming agents have been developed in the prior art forpreventing or minimizing difiiculties in paper manufacture caused byfoaming of the paper stock. Some of these compositions have enjoyedsubstantial commercial success, but it has been found that in certaininstances some of them do not give as satisfactory results as aredesired. For one thing some of these compositions are not as stable toacid conditions as is desired. This is a very important factor inasmuchas it is common practice in many paper mills to add alum, i. e. aluminumsulfate, to the paper stock in order to form an insoluble, waterrepellent aluminum resinate from the aluminum ion in the alum and thesodium resinate which is added to the paper stock. This insoluble waterrepellent aluminum resinate deposits upon the individual fibers of thepaper stock and thus aids in producing a paper having a certain degreeof water repellency. Since aluminum sulfate has a rather acid reaction,the addition of it to a paper stock causes the paper stock also to havean acid reaction. In many cases it is found that the paper stock willhave a pH of 4.5 or lower. The acidity of the paper stock tends to causeemulsions of defoaming agents to break and thus the defoaming agents notto remain uniformly dispersed in the paper stock. Furthermore, theingredients of such defoaming agents, after the emulsions thereof break,usually tend to rise to the upper portion of the paper stock inasmuch asthey have a specific gravity of less than one whereas the paper stockhas a specific gravity very close to one. In so concentrating in theupper portion of the paper stock, it seems that these ingredients tendto carry the pitch which is contained in the paper stock along with theminto the upper layers. Then when the sheet passes through the rolls ofthe paper machine, the pitch which appears to be concentrated in theupper surface of the sheet causes the sheet to stick to the rolls withthe result that the sheet often becomes torn or broken. With Fourdriniermachines very serious difficulties have been encountered when attemptingto control foaming in paper stocks having an acid pH. In particular, ithas been found that the paper sheet often tends to stick and to break atthe dandy roll and first press roll. Such sticking of the paper sheet atthe dandy roll and first press roll with the resultant breaking of thesheet is very undesirable, of course, since it causes a considerableloss of time in the paper making process and results in the damaging ofa considerable amount of paper.

Another disadvantage of certain of the prior art defoaming agents isthat they are not as stable when emulsified in hard water as is desired.This is an important factor since the defoaming agents in many cases areemulsified in water and placed in a suitable container above the sheeton the Fourdrinier machine and the defoaming agent allowed to slowlytrickle or flow from the container particular grade of paper.

into the paper stock. If the water which is used in forming the diluteemulsion from some of the concentrated defoaming agents of the prior arthas any appreciable degree of hardness, the defoaming agents tend tobreak out from the emulsion and rise to the top of the container. Thusthe solution of the defoamer which is running into the paper stock willnot contain a sufficient amount of the defoaming agent to efiectivelyprevent foaming until the greater part of the solution has run out ofthe container. At that time, the material which is running into thepaper stock will be much more concentrated than necessary. Thus in suchcases it will be found that the defoaming action of the solution will bevery irregular and will not be at all satisfactory. Another instancewhere it is necessary to have a defoaming agent which is stable to hardwater is when the defoaming agent is fed to the paper makin machines bymeans of a pump such as when it is desirable to feed the defoaming agentfrom one source to a number of machines. In such cases it has been foundthat the pipes leading from the container for the defoaming agent andfrom the pumping device to the various paper machines sometimes becomeclogged up since the hard water may cause breaking of the emulsion ofthe defoaming agent which remains in the pipes from one day to anotheror when the defoamer is not being used. When the emulsion breaks, someof the ingredients of the defoaming agent which separate therefrom tendto clog up the joints in the pipes. Then when it is desired to resumeoperations it is sometimes necessary to employ steam to clean out thepipes so that a free flow of the defoaming agent may be obtained. Stillanother instance where it is very desirable to have a defoaming agentwhich is stable to hard water is in the production of calcium carbonatefilled paper. Many grades of magazine paper contain as much as 15% ormore of calcium carbonate as a filler to impart a high degree ofopaqueness and a desirable finish to the paper. This calcium carbonateis usually incorporated into the paper stock, that is, when the paper isbeing made on a Fourdrinier machine, at the fan pump or in the whitewater from the trays. This large amount of calcium carbonatesubstantially increases the hardness of the water in the slurry and if adefoaming agent is being used which is not stable to hard water, theeffectiveness of the defoamer may be greatly impaired. Sticking of thesheet may occur at the dandy and first press rolls with resultingbreakage just as in the case when paper stock having a relatively acidpH is employed.

It has also been found that some of the defoaming agents of the priorart are not as stable to various inorganic salts as is desired. It isimportant in many cases that a defoaming agent which is stable toinorganic salts be available since it is common practice in manyinstances to add clays, carbonates (as mentioned above) and otherfillers to the paper stock in order to produce a Also as previouslymentioned, alum is frequently added to paper stock and it exerts a salteffect, of course, in addition to the acidity which it has. Furthermore,in many cases, paper manufacturers make various grades of paper fromused cardboard boxes and containers. Many of these paper containers,particularly corrugated boxes, etc., are made by binding various layersor sheets of paper together using adhesives such as sodium silicate.Thus pulp which is obtained from such used cardboard containers containsappreciable quantities of sodium silicate, thus adding to the saltconcentration present in the pulp and paper stock.

It is thus seen that there is a need for a new and improved defoamingagent which will be stable in acid conditions, in hard water and in thepresence of large amounts of inorganic salts.

It is the object of this invention to provide a new and improveddefoaming agent.

A further object of the invention is to provide a new and improveddefoaming agent which is stable in acid conditions as well as inalkaline conditions, which is stable in hard water and which is stablein the presence of relatively large amounts of inorganic salts.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

I have discovered that the above and other objects of the invention areaccomplished by providing a defoaming agent made up of a paraffinhydrocarbon containing at least 12 carbon atoms, e. g. a mineral wax, apartial ester of a polyhydric alcohol and a higher fatty acid, an esterof a lower monohydric alcohol and a higher fatty acid, a fatty acid monoester of a polyethylene glycol having a molecular weight of from about200 to about 4000 and water. It has been found in actual practice in thepaper mills that the compositions of the present invention are farsuperior to the compositions of the prior art whenever any of the threefactors referred to hereinabove, i. e., acid conditions, hard water, orpresence of relatively large quantities of inorganic salts, is present.The compositions of the present invention were found to eliminateentirely the troubles referred to above with regard to sticking andbreaking of the sheets at the dandy roll and first press roll onFourdrinier machines. In a number of mills the compositions of thepresent invention have substantially supplanted the compositions of theprior art whenever any of the adverse conditions referred to above arepresent.

In preparing the compositions of the invention, a mineral wax such asscale wax is preferably used; however, other parafiin hydrocarbonscontaining at least 12 carbon atoms such as paraffin oil, paraffin wax,microcrystalline wax, etc., are also very suitable either alone or inadmixture with scale wax. The scale wax can be admixed with a mineraloil such as parafiin oil so as to produce a softer product than would beobtained using a mineral wax alone. The mineral wax or other paraffinhydrocarbon or mixture of hydrocarbons should make up from about 3% toabout 15%, with from about 4% to about 10% being the preferred range, ofthe original concentrated semi fluid-like composition which is preparedfor shipment to the paper mills. The compositions can also contain asmall amount of other waxes which serves to modify the nature of themineral wax such as, for example, candelilla wax which has a highermelting point than the mineral wax. In most cases, however, it ispreferred that the compositions be prepared so that the concentratedproducts will be in more or less of a semi-fluid state so that they willbe more readily dispersible in cold water.

Another of the essential ingredients of the new defoaming agents is apartial ester of a polyhydric alcohol and a higher fatty acid such asglyceryl mono-oleate, glyceryl monostearate, glyceryl monoricinoleate,ethylene glycol monostearate, ethylene glycol mono-oleate, diethyleneglycol monostearate, diethylene glycol monooleate and mono esters offatty acids with polyhydroxy alcohols such as sorbitol, mannitol, etc.The fatty acid which is used in preparing these monoesters is a higherfatty acid, preferably one having at least 14 carbon atoms althoughfatty acids having from 14 to 22 carbon atoms are suitable. The fattyacid can be straight chain or branch chain and can be saturated,unsaturated, hydroxylated, etc. The expression partial ester is usedherein to connote an ester of a polyhydric alcohol in which at least oneof the hydroxyl groups remains free or unesterified. The concentratedcompositions as shipped to the paper mill should contain from about 3%to about 15% of such a partial ester with from about 5% to about beingthe preferred amount of such an ester in the concentrated compositions.

The fatty acid ester of a lower monohydric alcohol which makes upanother of the essential ingredients of the present compositions isprepared from fatty acids containing at least 14 carbon atoms, and fattyacids containing from 14 to 22 carbon atoms are suitably employed. Thefatty acid can be straight chain or branch chain and can be saturated,hydroxylated, unsaturated, etc. Alcohols suitable for preparing suchesters are alcohols containing 8 or less carbon atoms and which containonly one hydroxy group, e. g. methanol, ethanol, propanol, butanol,pentanol, hexanol, heptanol, octanol, and isomers of these variousalcohols. Preferably fatty acid esters of methanol are employed in viewof the relatively low cost of methyl alcohol in comparison to the costof the other monohydric alcohols; however, if desired, any of theotherabove monohydric alcohols can be used. Preferably the concentratedcompositions of the invention contain from about 3% to about 15% ofthese monohydric alcohol esters and in 10st instances from about 4% toabout 10% of such an ester is present in the concentrated compositionsof the invention.

The esters of a polyethylene glycol which make up a further essentialingredient of the compositions of the invention are either the mono orthe diesters of the particular polyethylene glycol being employed. Theseesters are prepared from fatty acids containing from 14 to 22 carbonatoms and from polyethylene glycols having a molecular weight of fromabout 200 to about 4000. Thus polyethylene glycols having molecularweights of from about 200 to about 4000 are either mono or diesterifiedwith fatty acids such as oleic acid, stearic acid, palmitic acid,ricinoleic acid, etc. to form the polyethylene glycol esters used inpreparing the compositions of the invention. The concentratedcompositions of the invention as shipped to the paper mill shouldcontain from about 3% to about 15% of such esters with from about 4% toabout 10% being the preferred amount of such esters in the concentratedcompositions of the invention.

The remainder of the compositions of the invention is made upsubstantially of water although small amounts of materials such asformaldehyde, which may be added as a preservative, and various othermaterials may be added to the compositions if desired. The compositionsof the invention as shipped to the paper mill will in most cases containfrom about to about of water.

In forming the compositions of the invention, the in; gredients thereofwhich are solids are melted and then those ingredients of thecompositions which are liquids are admixed with the melted materials. Itis preferred to admix all of the nonaqueous materials at a temperatureat which all of these materials are liquid, prior to admixing the watertherewith. However, any suitable order of steps in admixing the variousingredients to produce the defoaming agents of the invention can beutilized. The final concentrated product which is obtained will be inmost cases a white, semi-fluid material at room temperature.

The concentrated product, when it is used by the paper mill, ispreferably diluted with water until the nonaqueous ingredients make upfrom about 0.5% to 1% by weight of the diluted emulsion although muchmore dilute emulsions, e. g. 0.02% to 0.1%, can be used as is apparentfrom Example I appearing hereinafter. The compositions of the presentinvention are very readily dispersible in additional water merely bygently agitating the concentrated product with water preferably at atemperature of about F. This is another substantial advantage of theproducts of the present invention over some of the prior art productssince it is necessary when diluting some of the prior art defoamers toemploy considerable agitation and to heat the water which is to beadmixed therewith to a temperature of at least F. Thus it is seen thatthe compositions of the present invention are readily diluted prior touse in the paper mill.

The diluted compositions are preferably added to the paper stocksuspensions in such an amount so that the non-aqueous materials of thedefoaming agent are present in an amount of from about 1 to about 5parts per million parts of the paper stock suspension or from about0.01% to about .05 of the dry weight of the pulp in the stocksuspension. The diluted emulsions can be added as needed and in anydesired manner, however, to a paper making machine such as a Fourdrinieror cylinder type machine and they will very effectively inhibit theformation of undesirable foam under nearly all conditions of operation.

For a fuller understanding of the nature and objects of the invention,reference may be had to the following examples which are given merely asfurther illustrations of the invention and are not to be construed in alimiting sense.

Example I A concentrated defoaming agent was prepared by admixing 5parts of a scale wax having a melting point of 124126 F., 5 parts ofparaffin oil, 5 parts of glyceryl monostearate, parts of methylricinoleate, 10 parts of the monostearate ester of a polyethylene glycolhaving a molecular weight of approximately 400, 64.6 parts of water and0.4 parts of 40% aqueous formaldehyde. The composition was prepared byadmixing the first five ingredients at a temperature of about 60 C. atwhich temperature all of these materials were in a fluid condition. Tothe clear mixture, the water was added slowly at 60 C. with stirring.Agitation of the mixture was continued as the material was allowed tocool to about C. Then the small amount of formaldehyde which served as apreservative was admixed with the defoaming agent. The product which wasobtained was a white, semi-fluid material at room temperature.

This composition was readily diluted with additional water at atemperature of 100 F. to form a dilute emulsion containing 0.1% of theabove product. This dilute emulsion was sprayed upon the wire of aFourdrinier machine at a point about 5 to 15 feet from the slice.Substantially no foaming developed and it was found that no stickingwhatever occcurred at the dandy roll or first press roll and thus nobreaking whatever of the sheet occurred even after several hours ofcontinuous running of the machine. The pulp which was being usedcontained a moderate amount of alum and had a pH of 6.7. Prior to theuse of the compositions of the present invention, this mill had had veryserious difficulties when manufacturing paper from this paper stock.

The defoaming agent of this example was also used with a very highdegree of success on several other machines in the same paper mill whichwere producing paper from various types of paper stocks. The pH of thesestocks varied from neutrality to a pH of 5; several of them containedfairly large amounts of rosin size and alum; and several of themcontained large amounts of clay and/or calcium carbonate as fillers,etc. The defoaming agent of the present invention gave uniformlyexcellent results under these rigorous conditions.

Example II Another composition of the invention was prepared insubstantially the same manner as the composition of Example I. Thecomposition of the present example, however, contained 2.5 parts ofscale wax, 2.5 parts of paraflin oil, 8 parts of the mono ester ofglycerine formed by reacting one mole of monohydroxystearic acid withone mole of glycerine, 5 parts of methyl ricinoleate, 5 parts of themonostearate ester of a polyethylene glycol having a molecular weight ofapproximately 400, 0.4 part of aqueous formaldehyde and 76.6 parts ofwater. This composition was a very excellent defoamer as was shown byits very outstanding performance when tested by the glue test which isfrequently used to determine the 6 effectiveness as a defoamer of acomposition which is believed to have defoaming properties. This test iscarried out by admixing parts of water, 10 parts of glue and 5 parts ofa 2% solution of the material whose defoaming effectiveness is to bedetermined. This mixture is then placed into a 250 cc. low form beakerand rapidly agitated for 1 minute. The height of the foam in mms. ismeasured after the mixture is agitated for 1 minute and then at 1 minuteand 2 minute intervals after the agitation of the mixture has ceased. Itwas found that the composition of Example II was a very effectivedefoamer since after agitating a mixture containing 85 parts of water,10 parts of glue and 5 parts of a 2% aqueous emulsion of the compositionof the example, only 5 mms. of foam were present on top of the mixture.One minute after agitation had ceased all of the foam in the beaker hadentirely disappeared. A corresponding test which was run using parts ofwater and 10 parts of glue with no defoamer present gave 28 mms. of foamon top of the mixture after 1 minute of agitation. The entire amount offoam remained on top of this mixture even after the mixture was allowedto stand for 2 minutes after agitation had ceased. Thus it was apparentthat the composition of Example II was a very effective defoaming agent.

Example 111 Another one of the excellent defoamers of the presentinvention has the following formula:

Another product of the invention was prepared containing an antichlor(an agent to remove the influence of any residual chlorine in the paperstock). In some paper mills it is believed that residual chlorine in thepaper stock system from the bleaching plant helps to cause a bad foamcondition. Sodium thiosulfate (Na2S2Oa.5HzO) was incorporated into thefollowing defoaming agent of the invention to aid in overcoming the foamcondition caused by such residual chlorine:

Parts Scale wax 1.5 Paraflin oil 2.5 Glycerol mono ester ofhydroxystearic acid 6.5 Methyl ricinoleate 4.0 Monostearate ester of apolyethylene glycol having a molecular weight of about 400 4.0N212S2O3.5H2O 4.0 Water 77.1 Formaldehyde (40% aqueous) 0.4

Example V Three other products illustrating the novel defoamers of myinvention have the following compositions:

Parts Parafiin wax 8 Glyceryl mono-oleate 9 Butyl palmitate 8Monolaurate ester of a polyethylene glycol having a molecular weight ofabout 200 12 Water 63 B Parts Paraffin wax 12 Glyceryl monopalmitate 6Ethyl oleate 9 Dilaurate ester of a polyethylene glycol having amolecular weight of about 1000 The effectiveness of the three aboveproducts as defoaming agents was determined by the glue test as outlinedin Example II hereinabove. As in Example II, a concurrent test was madeon a glue solution which had not had a defoaming agent added thereto(this is referred to as the Blank in the following tabulation of theresults). The results of these tests are as follows:

Height of Foam in Mms.

After One One Minute Two Minutes Minute of After Agita- After Agita-Agitation tion Ceased Lion Ceased Blank 29 29 Product A 10 9 8 Product B12 11 10 Product 9 7 Although the products of the invention are ofparticular value for the prevention and elimination of foam in variousphases of paper manufacture, they are also excellent defoamers for manyother purposes. They readily and effectively eliminate foam in manytypes of aqueous mixtures which are encountered in industry. As isevident from the above examples, the products of the invention veryeffectively eliminate foaming in aqueous glue solutions.

Having described my invention what I claim as new and desire to secureby Letters Patent is:

1. A defoaming agent for pulp and paper stock consisting essentially ofan aqueous emulsion made up of from about 3 parts to about parts of aparaffin hydrocarboncontaining at least 12 carbon atoms, from about 3parts to about 15 parts of a partial ester of a polyhydric alcohol and afatty acid having from 14 to 22 carbon atoms, from about 3 parts toabout 15 parts of a fatty acid ester of a monohydric alcohol containingnot more than 8 carbon atoms and a fatty acid containing from 14 to 22carbon atoms, from about 3 parts to about 15 parts of an ester of apolyethylene glycol having a molecular weight of from about 200 to about4000 and a fatty acid containing from 14 to 22 carbon atoms, and waterwith the amount of water in the emulsion not exceeding about 99.98% ofthe emulsion.

2. A defoaming agent for pulp and paper stock consisting essentially ofan aqueous emulsion made up of from about 3 parts to about 15 parts of amixture of a mineral wax and a mineral oil, from about 3 parts to about15 parts of a partial ester of a polyhydric alcohol and a fatty acidhaving from 14 to 22 carbon atoms, from about 3 parts to about 15 partsof a fatty acid ester of a monohydric alcohol containing not more than 8carbon atoms and a'fat't'y acid containing from 14 to 22 carbon atoms,from about 3 parts to about 15 parts of an ester of a polyethyleneglycol having a molecular weight of from about 200 to about 4000 and afatty acid containing from 14 to 22 carbon atoms, and water with theamount of water in the emulsion not exceeding about 99.98% of theemulsion.

3. A defoaming agent for pulp and paper stock consisting essentially ofan aqueous emulsion made up of from about 3 parts to about 15 parts of amineral Wax, from about 3 parts to about 15 parts of a monoglyceride thefatty acid radical of which contains from 14 to 22 carbon atoms, fromabout 3 parts to about 15 parts of a methyl ester of a fatty acid havingfrom 14 to 22 carbon atoms, from about 3 parts to about 15 parts of anester of a polyethylene glycol having a molecular weight of from about200 to about 4000 and a fatty acid containing from 14 to 22 carbonatoms, and water with the amount of water in the emulsion not exceedingabout 99.98% of the emulsion.

4. A defoaming agent for pulp and paper stock consisting essentially ofan aqueous emulsion made up of from about 3 parts to about 15 parts of amixture of a mineral wax and a mineral oil, from about 3 parts to about15 parts of a monoglyceride the fatty acid radical of which containsfrom 14 to 22 carbon atoms, from about 3 parts to about 15 parts of amethyl ester of a fatty acid having from 14 to 22 carbon atoms, fromabout 3 parts to about 15 parts of an ester of a polyethylene glycolhaving a molecular weight of from about 200 to about 4000 and a fattyacid containing from 14 to 22 carbon atoms, and water with the amount ofwater in the emulsion not exceeding about 99.98% of the emulsion.

5. A defoaming agent for pulp and paper stock consisting essentially ofan aqueous emulsion made up of from about 3 parts to about 15 parts of amineral wax, from about 3 parts to about 15 parts of glycerylmonostearate, from about 3 parts to about 15 parts of methylricinoleate, from about 3 parts to about 15 parts of an ester of apolyethylene glycol having a molecular weight of between about 400 andabout 1000 and a fatty acid containing from 14 to 22 carbon atoms, andwater with the amount of water in the emulsion not exceeding about99.98% of the emulsion.

6. A defoaming agent for pulp and paper stock consisting essentially ofan aqueous emulsion made up of from about 3 parts to about 15 parts of amineral wax, from about 3 parts to about 15 parts of the monoglycerideof monohydroxystearic acid, from about 3 parts to about 15 parts ofmethyl ricinoleate, from about 3 parts to about 15 parts of an ester ofa polyethylene glycol having a molecular weight of between about 400 andabout 1000 and a fatty acid containing from 14 to 22 carbon atoms, andwater with the amount of water in the emulsion not exceeding about99.98% of the emulsion.

7. A defoaming agent for pulp and paper stock consisting essentially ofan aqueous emulsion made up of from about 3% to about 15% of a parafl'inhydrocarbon containing at least 12 carbon atoms, from about 3% to about15 of a partial ester of a polyhydric alcohol and a fatty acid havingfrom 14 to 22 carbon atoms, from about 3% to about 15 of a fatty acidester of a monohydric alcohol containing not more than 8 carbon atomsand a fatty acid containing from 14 to 22 carbon atoms, and from about3% to about 15% of an ester of a polyethylene glycol having a molecularweight of from about 200 to about 4000 and a fatty acid containing from14 to 22 carbon atoms, the balance of the emulsion being substan-'tially all water.

8. A defoaming agent for pulp and paper stock consisting essentially ofan aqueous emulsion made up of from about 3% to about 15% of a mineralwax, from about 3% to about 15% of a monoglyceride the fatty acidradical of which contains from 14 to 22 carbon atoms, from about 3% toabout 15% of a methyl ester of a fatty acid having from 14 to 22 carbonatoms, and from about 3% to about 15 of an ester of a polyethyleneglycol having a molecular weight of from about 200 to about 4000 and afatty acid containing from 14 to 22 carbon atoms, the balance of theemulsion being substantially all water.

9. A defoaming agent for pulp and paper stock consisting essentially ofan aqueous emulsion made up of from about 3% to about 15% of a mineralwax, from about 3% to about 15 of glyceryl monostearate, from about 3%to about 15% of methyl ricinoleate, and from about 3% to about 15 of anester of a polyethylene glycol having a molecular weight of betweenabout 400 and about 1000 and a fatty acid containing from 14 to 22carbon atoms, the balance of the emulsion being substantially all water.

10. A defoaming agent for pulp and paper stock consisting essentially ofan aqueous emulsion made up of from about 3% to about 15% of a mineralwax, from about 3% to about 15% of the monoglyceride ofmonohydroxystearic acid, from about 3% to about 15 of methylricinoleate, and from about 3% to about 15% of an ester of apolyethylene glycol having a molecular Weight of between about 400 andabout 1000 and a fatty acid containing from 14 to 22 carbon atoms, thebalance of the emulsion being substantially all water.

11. A defoarning agent for pulp and paper stock consisting essentiallyof an aqueous emulsion made up of from about 3% to about 15% of amixture of a mineral Wax and a mineral oil, from about 3% to about 15%of glyceryl monostearate, from about 3% to about 15% 10 of methylricinoleate, and from about 3% to about 15% of an ester of apolyethylene glycol having a molecular Weight of between about 400 andabout 1000 and a fatty acid containing from 14 to 22 carbon atoms, thebalance of the emulsion being substantially all water.

12. A defoaming agent for pulp and paper stock consisting essentially ofan aqueous emulsion made up of from about 3 to about 15% of a mixture ofmineral wax and a mineral oil, from about 3% to about 15% of themonoglyceride of monohydroxystearic acid, from about 3% to about 15 ofmethyl ricinoleate, and from about 3% to about 15 of an ester of apolyethylene glycol having a molecular weight of between about 400 andabout 1000 and a fatty acid containing from 14 to 22 carbon atoms, thebalance of the emulsion being substantially all water.

i eferences Cited in the file of this patent UNITED STATES PATENTS2,298,465 Clapsadle Oct. 13, 1942 2,304,304 Fritz Dec. 8, 1942 2,346,928Lighthipe Apr. 18, 1944 2,390,212 Fritz Dec. 4, 1945 2,563,857 McGrinnAug. 14, 1951 OTHER REFERENCES Chemicals by GlycoGlyco Products Co., N.Y. (1948), pages 12-14.

1. A DEFOAMING AGENT FOR PULP AND PAPER STOCK CONSISTING ESSENTIALLY OFAN AQUEOUS EMULSION MADE UP OF FROM ABOUT 3 PARTS TO ABOUT 15 PARTS OF APARAFFIN HYDROCARBON CONTAINING AT LEAST 12 CARBON ATOMS, FROM ABOUT 3PARTS TO ABOUT 15 PARTS OF A PARTIAL ESTER OF A POLYHYDRIC ALCOHOL AND AFATTY ACID HAVING FROM 14 TO 22 CARBON ATOMS, FROM ABOUT 3 PARTS TOABOUT 15 PARTS OF A FATTY ACID ESTER OF A MONOHYDRIC ALCOHOL CONTAININGNOT MORE THAN 8 CARBON ATOMS AND A FATTY ACID CONTAINING FROM 14 TO 22CARBON ATOMS, FROM ABOUT 3 PARTS TO ABOUT 15 PARTS OF AN ESTER OF APOLYETHYLENE GLYCOL HAVING A MOLECULAR WEIGHT OF FROM ABOUT 200 TO ABOUT4000 AND A FATTY ACID CONTAINING FROM 14 TO 22 CARBON ATOMS, AND WATERWITH THE AMOUNT OF WATER IN THE EMULSION NOT EXCEEDING ABOUT 99.98% OFTHE EMULSION.